1. Field of the Invention
The present invention relates to a disk device installed in a server or the like.
2. Description of the Related Art
Today an information processing technology advances and information processing devices are widely used. In such a situation, the large capacity of servers for electronically providing services is promoted and the collective process of lots of information is requested. In order to collectively process lots of information, a hard disk for storing a large amount of data is needed. Therefore, a server in which a plurality of hard disk devices is installed in the same cabinet is widely used.
FIG. 1 shows the conceptual configuration of the conventional server.
As shown in FIG. 1, a server 11 comprises a host 10 for performing a major data process and n hard disk drives (HDD drives-1˜n) for data to be processed by the host 10, already processed data and the like. Conventionally, each hard disk drive is directly connected to the host 10 and information is exchanged between the host 10 and each hard disk drive. In this case, no internal information is bi-directionally communicated/exchanged among the hard disk drives. However, if a plurality of hard disk drives is installed in the same cabinet, vibration caused by the operation of a specific hard disk drive sometimes travels to another hard disk drive. In this case, vibration caused by the seek operation of an adjacent hard disk drive affects the positioning of the head of another hard disk drive.
Conventionally, since a plurality of hard disk drives are independently operated, no internal information cannot be bi-directionally communicated/exchanged among the hard disk drives. When external vibration due to the operation of another hard disk drive is large, writing occurs in the relevant hard disk drive. In this case, there is a possibility that swing writing (a state where the head swings during writing) or distorted writing (a state where the head position deviates from the home position) occurs in the relevant hard disk drive. There is the concept of an autonomous disk, in which an interface or interface controller in its higher-layer exchanges information among hard disk drives. In this case, the response of a hard disk delays by a time taken for information to be exchanged among hard disk drives via the higher layer.